Furnace construction and control means therefor



Oct. 1, 1935. J. w. NoRRls FURNACE CONSTRUCTION AND CONTROL MEANSTHEREFOR Filed March 26, 1934 TO H EAT FA N PLANT Patented Oct. l, 1935Parri-:NTl oFI-Ic-F.V

FURNACE CONSTRUCTION AND'CONTROL M'EANS THEEEFOR John W. Norris,Marshalltown, Iowa, assigner to Lennox Furnace Company, Marshalltown,Iowa,

a corporation Application Maren ze, 1934, vsemi No. 711,373

12 claim (ci. 236-11) The object of my invention is to provide a furnaceconstruction and control means therefor which are simple, durable andcomparatively inexpensive to manufacture.

A further object is to provide a furnace so constructed that aircirculation can be maintained but temperature in various rooms or zonesof a building or the like may be accurately controlled by individualthermostats located in the various zones, the control means beingoperable to vary the temperature' of the air being circulated to thevarious zones rather than its volume.

Still a further object is to provide means for practically continuouslycirculating air through rooms or the like in connection with a furnaceof special construction from which both hot air and tempered air can besupplied, the various zones to which theY air is supplied being eachprovided with an individual thermostat which determines whether hot airor tempered air shall be supplied to the zone, the determination, ofcourse, being responsive to the temperature requirements of the zone,whereby to maintain the zone at an even temperature, the heat generatorbeing automatically controlled so as to operate when anyone of the zonesrequires heat.

Still a further object is to provide a modied form of construction whichwill either circulate the air in the various zones without heating it,or both circulate and heat it as required, depending on the temperatureconditions of the various zones.

With these and other objects in view my invention consists in theconstruction, arrange- -ment and combination of the various parts ofreference numeral I0 to indicate the body portion of a furnace. The bodyportion I0 has in it a combustion chamber or compartment I2 and acompartment I4 for ashes or automatic fuel burning mechanism. The usualheat radiator is provided, as indicated at I6, through which the smokeor other products of combustion pass before entering the chimney in theordinary manner. Speciiic details of this are not shown on the drawingas it comprises no part of my present invention. 5

Surrounding the body portion I0 of the furnace is an inner casing I8having a cone-shaped head 20 and a restricted neck 22. Above the neck 22and communicating with it a plenum chamber 24. Hot air conduits 26 leadfrom the plenum l0 chamber 24 to various rooms or other zones of abuilding. Only two of the hot air conduits 26 are illustrated, it beingunderstood, oi course, that any number desired can be used.

Surrounding the inner casing I8 is an outer 15 casing 28 having areduced portion 30 and a restricted neck 32. A tempered air chamber 34surmounts the restricted neck 32 and communicates with it, passageways36 being provided for conducting air from the chamber 34 to the 20conduits 26. The air flowing between the casings I8 and 28 is indicatedby dotted line arrows and may be called tempered air.

A cold air shoe is illustrated at 38. Withinit a blower housing 46 isprovided having inlet open- 25 ings 42. A blower rotor is indicated at44, while the outlet for the blower is indicated at 46.

The outlet 46 communicates with the outer casing 28, while the innercasing I8 is provided with an opening 48 in substantial alignment with30 the outlet 46 but spaced from it as clearly shown.

It is thus possible for part of the air from the blower to pass betweenthe combustion compartment I2 and the casing I8 and part through thespace between the casings I8' and 28, the casing 35 I8 being providedwith openings 50 spaced circumferentially around it for the purpose ofpermit/ting the air 'from the blowerto be distributed to the temperedair space.

A cold air pipe 54 leads from the various rooms 40 or zones to which thehot air conduits 26 lead.

A pipe 56 can be provided for taking in a small regulated amount ofoutside air so as to maintain a slight pressure in the zones -to beheated for causing outward rather than inward leakage ow. A pipe 58drops from the pipes 54 and 56 to the cold air shoe 38.

Automatic damper motors 66 and 60a are provided. having damper shafts 62and 62a provided with dampers 64 and 64a. Where additional 5.0 pipes 26lead from the plenum chamber 24, additional damper motors and dampersare provided.

It will be noted that the dampers -64 and 64a are adapted to closeeither communication from Ithe plenum chamber. to the hot air pipe 265.5.1

or from the tempered air chamber 34 to the pipe.

For automatically controlling the damper motors 60 and Gla, I provideroom thermostats 10 and 10a, each located at an advantageous point inthe zone to which its respective hot air pipe leads. The thermostatsmaybe of the three wire type for causing rotation of the damper motorsin either one direction or theV other, or of the two wire type when thedamper motors are of the automatic return type.

The current for the motors 6l and 80a is preferably low tension and canbe supplied from a transformer 12 or any other suitable source of power.

As shown in Figure 2, current supply wires extend to heat plant. Thesemay control an automatic coal stoker, automatic gas or fuel oil burnersor the like. The heat plant may be termed as a heat generator for thepurpose of my claims wherein the term refers to the furnace and thecasing i8 within which the air is heated.

It is desirable to control the heat generator from each thermostat sothat when any one thermostat calls for heat, the heat generator will beoperative. Provision can be made for this by providing on the dampermotor 8U, contacts 66 and 68 engageable when the room thermostat 10 isin cold position and cause the damper to swing to hot air positionrather than its normal tempered air position. The damper motor a islikewise equipped with contacts 66a and 68a.

- If it is desirable, as for instance when the damper motor operatesslowly, to close the heat generator circuit immediately uponcommencement of the damper from normal position to hot air position, thecontacts can be arranged as in Figure 4 wherein the damper motor holdsthe contacts separated when in tempered air position, but immediatelyVallows them to close when it starts to move toward hot air position.

Although it is desirable to maintain circulation of tempered air when`any particular zone is notrequiring hot air, the furnace can beconstructed so that the air already in the zone can be' circulatedwithout being tempered, Figure 3 showing such a construction. In thisiigure, instead of using the casing 28, a conduit 28a is providedthrough which the air, without being tempered, can flow from the blower40 to a cold air chamber 34a.

A "fan control" and a "limit control are also preferably provided forthe fan and the heat generator, respectively.

Practical operation` The thermostat Il is in normal position, the heatrequirements for the zone in which it is located rbeing satisfied. 'I'hethermostat '10a is indicated in its heat requiring position whereby ithas energized the motor ila and caused the ldamper a to move to positionfor the ilow of hot air to the zone for the thermostat 10a rather thantempered air, the contacts a and a -being engaged for operating the heatgenerator.

It will be noted that the limit control is in series with the contacts-a and 68a. Accordingly, when the limit control reaches a predeterminedhigh temperatlne, it will cut on the current to the heat plant, it beingset for operatinzml at about 140. This prevents any overheating or"overrunning of the heat generator.

When the heat requirements of the zone for the thermostat 10a aresatisfied, the thermostat will move to its opposite position forreturning the damper a to its normal position.

It will be noted that in either position, the air is free to circulate,but itsy temperature is con- :sv

trolled by the position of the Idamper even though the volume of airremains the same. Thiais quite important to eliminate stratification ofthe air in the room and prevent what is known as cold '10".

'Ihe blower I4 is not an essential part of my lo invention as theinvention vcan be applied to gravity circulation as well as forced aircirculation. In either case, the temperature of the air is controlledin'the individual zones by supplying either tempered air or hot airthereto. l5

Although not as satisfactory, the construction of Figure 3 eitherre-circulates the air or both heats and re-circulates it, thus providingcontinuous circulation, although not as good and eilicient temperaturecontrol for the individual 20 zones. Y'

Some changes may be made in the construction and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by 25 my claims, anymodiiied forms of structure or use of mechanical equivalents, which maybe reasonably included within their scope.

I claim as my invention: I

l. In a device of the class described, a heat 30 generator for aplurality of zones, hot air conduits from said heat generator to saidzones, means for continuously maintaining circulation of air from and tosaid zones and through said hot air conduits, a means responsive to thetemperature of each zone for controlling the temperature of the airsupplied from the hot air conduits to the zones and means forcontrolling said heat generator, said last means being operable to causethe heat generator to operate when any of said 40 means responsive tothe temperature of each zone is in position for raising the temperatureof the air supplied from the hot air conduit to that zone.

2. In a device of the class described, a heat generator for a pluralityoi' zones, hot air 'conduits 45 from said heat generator to said zones,means for continuously maintaining circulation of air from and to saidzones and through saidhot air oonduits, ,damper means movable to causethe circulated air to pass through the heat generator or by-pass it andmeans for controlling said heat generator, said last means beingoperable to cause operation of the heat generator only when one or moreof said damper means is in podtion causing thecircuiated air to passthrough said heat generator.

3. In a device of the class described, a heat generator for a pluralityof zones, Vhot air conduits from said heat generator to said zones,means for continuously maintaining circulation of air from 00 and tosaid zones and through said hot air conduits. damper means each movableto control circulated air to cause it to pass through said heatgenerator or by-pass it, means for controlling said heat generator, saidlast means being operable to cause operation of the heat generator onlywhen one or more of said damper means is in position causing thecirculated air to passthrough said heat generator, each damper meansbeing only responsive to the temperature of the zone, the 7 air forwhich it controls.

4. In a device of the class described, a heat generator for a pluralityof zones, a casing therearound a dspaoed therefrom, hot air conduitsfrom said eat generator tol said zones, means for fil continuouslymaintaining circulation of air from and to said zones and through saidhot air conduits and damper means movable to cause the circulated air'to each zone to either entirely pass between the outer surface of saidheat generator and said casing or to entirelyl pass over the outersurface of said casing.

5. In a device of the class described, a heat generator for a pluralityof zones, a casing therearound and spaced therefrom, hot air conduitsfrom said heat generator to said zones, means for continuouslymaintaining circulation of air from and to said zones and through saidhot air conduits and damper means movable to cause the circulated air toeach zone to either entirely pass between the outer surface of said heatgenerator .and said casing or to entirely pass over the outer surface ofsaid casing, one damper means being provided for each zone andcontrolled in response to the temperature thereof.

6. In a device of the class described, a heat generator for a pluralityof zones, a casing therearound and spaced therefrom, hot air conduitsfrom said heat generator to said zones, means for maintainingcirculation of airfrom said zones over the outer surface of said heatgenerator or over the outer surface of said casing and through said hot.air conduits back to said zones and means responsive to the temperatureof each zone for controlling the iiow of the air to cause it to eitherpass over the heat generator or over the casing.

'7. A furnace construction comprising a combustion compartment, a hotair chamber therearound, a tempered air chamber around the hot airchamber, conduits from the two chambers and means to control the now ofair from the two chambers to each of said conduits, causing the air toeach one to ow from either chamber to the exclusion of iiow from theother one.

8. A furnace construction comprising a combustion compartment, a hot airchamber therearound, -a tempered air chamber around the hot air chamber,conduits from the two chambers, damper means to control the flow of airfrom the two chambers to the conduits and a temperature responsive meanslocated in the zones to which 4the conduits lead, to control each dampermeans for the respective zones and thereby cause individual fiow ofeither hot air or tempered air only to each zone.

9. A furnace construction comprising a combustion compartment, a hot airchamber there- 5 around, a second chamber around the hot air chamber,conduits from the two chambers and means to control the flow of air fromthe two chambers to said conduits and thereby cause individual flow ofeither hot air or tempered air 10 only to each zone.

10. A furnace construction comprising a combustion compartment, a hotair chamber therearound, a second chamber around the hot air chamber,conduits from the two chambers, damp- 15 er means to control the flow ofair from the two chambers to the conduits and a temperature responsivemeans. locatedin the zones to which the conduits lead, to control. eachdamper means for the respective zones and thereby continuous individualflow of either hot or tempered air only to each zone.

11. In a device of the class described, a heat generator forv supplyingheat to a plurality of zones at a plurality of different temperatures, a25 control means therefor, hot air conduits from said heat generator tosaid zones,I a blower for maintaining circulation of air from saidzonesand through said hot air conduits back4 to said zones plied to therespective hot air conduits by causing supply at various of saidtemperatures and to control said rst control means. I 12. In a deviceofthe classdescribed, a heat 3 generator for supplying heat to aplurality of zones at a plurality of different temperatures, hot airconduits from said heat generator to said4 zones, a blower formaintaining circulation of air from said zones and through said hot aircon- 40 duits back to said zones, damper means movable to cause thecirculated air to be supplied at one or another of said temperatures andmeans 'responsive to the temperature of. each zone for controlling saiddamper means and thereby the temperature of air supplied from therespective hot air conduits.

, JOHN W. NORRIS.

